Projectile.



No. 386,637. Patented Nov. I2, 961.

A. J. ROBERTSON.

PROJEGTILE.

(Application filed Sept. 25, 1900., (No HodaL) WITNESSES IN VENTOI? Y is1-1 fir- 1 Ni i E i ATIES ARCHlSnl-D 0F GHQ-ll! Li TO ALFR-LD (l. REX,OF PHILADELPHXA, PENNSYLVANIA.

#SEECIEICATXGN forming 399.1. ot' Iiretters Patent No. 686,637, datedNovember 12, 19m. Application filed September 25, 1900- Serial No.31,099. (No mudelJ To all whom it may concern:

Be it known that I, ARCHIBALD J. Bonner- SON, a. subject of the Queen ofGrectBritain, and e. resident of the city and county of Philadelphia.end State of Pennsylvcnizt, have invented certain new and useful In]provouieuts in Projectiles, of which the following is 2i specificetion.

This invention relates to projectiles for use in warfare; and itconsists in certain-peculiarities of the construction, novelarrangencnt, and operation of its parts, as will be ing nh'lity of theprojectiles and causing the points to drop in it molten mess. it istherefore the principal object or" my invention to prevent thisnieitingof the points of the pro jcctilcs em give them a maximumpiercing ability by providing the points of the projcctiles with out gedges, so that the inipact immediately lesions the projectile to theplate, tl us securing to t is projectile all the elements of(iostructionnau1ely, the footscconds velocity and the rotary motion.--irhcrebv when th i npnct occurs the projectile isiui stolyfzistencdsndinipnrts motionto the pic egv' iiethertiie rojeciile strikes thedefensive object or plate at right angle or an conic angle, it obviousthat a projectile constructed sccor..ing to my invention would engagethe plate, while a smoothpointcd projectile would glance therefrom.

o the accompanying drawings, e'" in elevation the pointed I i bodying myinvention. VlOW oi the projectile which fills the e L tire on .1 Y endFig. is with the grooves in t is tired and D is a. hand, preferably ofcopper, such {LS is commonly used to impart rot-cry motion toprojectiles.

In order to accomplish the purposes of my invention, 1 provide two ormore cutting edges B on the pointed end of the projectile, which is doneby depressing the material of which the projectile is composed on lineswhich begin at the extreme point of the projoctiie and from said pointextend rcarwardly in helical or spirallycurved lines until the extremeclismcterof the projectile is reached. On one side of each of theselines the solid metal of the projectile is reduced ton dooth sufiicicntto form an edg'cnud turnish a clear ance for the chips cut out of theobject being pierced. These depressions begin at the inner portion ofthe cutting edges and extend to the outer portion of the next oradjecent cutting edge, thus forming cutting edges backed up by solidwalls, furnishing great power of resistance. Nhen the point of theprojectile is thus finished, it is then tempered to a maximum degree ofhardness.

These cutting edges are not employed for the purpose of giving rotarymotion. to the projectile when passing through the air, but for thepurpose oi engaging the plate in order to iii: the projectile therein assoon as it strikes the object of resistance, and the projectile mayreceive its rotary motion through the medium of it ride-bored gun. As isWell known, projectiles discharged from guns of thc-obove'nnmedcharacter rotate from left to right, and I therefore form the cuttingedges so that their faces will he presented in the direction in whichthe projectile is rotated, thus causing the projectile to pose trcte thesurface of the ploteond. fasten itself therein, thus delivering to thepinto through the projectile the concentrated eiicct of im- 2 eeeeevpact-pressure, rotary motion, and vibration, ting edges formed bydepressing the matethe concentration of all its elements of de riel infront thereof said depressions beginsti'uction. ning at the innerportion of one of the cut- Heving thus fully described my invention,ting edges and. extending to the outer por- 5 what I claim as new, anddesire to secure by tion of the adjacent cutting edge, substan- 15Letters Patent, istielly as described.

A pointed projectile having cutting edges ARGHIBA'LD RGBERTSON.extending helically oi spirally from the ex- "Witnesses: trenie pointrearwerdly to the extreme cliem- CHAS. M. RHODES, 1o eter of the body ofthe projectile, said cut- ALFRED G. REX.

